Microfibrillar cellulose (MFC), the most common microfibrillar polysaccharide, is prepared from wood fibres that have been delaminated to small fragments with a large proportion of the microfibrils of the fibre walls uncovered.
The produced MFC has a high specific surface area that imparts strong binding capacity in paper and fibre structures, high water retention, good stability in water dispersions as well as high viscosity.
The cellulose fibres can be delaminated to microfibrillar cellulose by enzyme treatment, especially by treatment with cellulases which is disclosed in WO 2004/055268. However, delamination of fibres by means of enzyme treatment is many times expensive and/or inefficient.
It would be desired to provide a method that could increase the production capacity in view of the prior art methods in which inter alia fibre clogging has impeded such attempts. It would also be desired to provide a method of preparing microfibrillar cellulose with an increased product consistency, i.e. to provide a suspension having a higher concentration of microfibrils without suffering from fibre clogging, increase in temperature and/or pressure resulting in interruption of the production. It is a further objective to provide a method of preparing MFC having an increased surface charge and stability in view of MFC products known in the art. The present invention intends to provide such a method.